Various needs for display devices are increasing with the development of information society and in response to the needs, various display devices such as a liquid crystal display (LCD), plasma display panel (PDP), an electro luminescent display (ELD) and vacuum fluorescent display (VFD) has recently been developed and is being used.
Among others, the liquid crystal panel of the LCD includes, a liquid crystal layer, a TFT substrate and a color filter substrate that face each other, with the liquid crystal layer therebetween, and since the liquid crystal panel is not self-emissive, it is possible to use light provided from a backlight unit for displaying a picture.
A light source installed at the backlight unit may be one of a light emitting diode (LED) chip and an LED package including at least one LED chip.
Recently, a flat fluorescent lamp (FFL) or surface light source (SLS) is being actively applied to a light source for the LCD panel. A surface light source is perceived as a light source having a uniformly shiny surface and no thickness, and since the backlight unit is thinned by the using of the surface light source, it is possible to achieve thinness in a display device.
Also, a light guide layer configuring the backlight unit has typically been filled with separate transparent resins but a backlight unit including a light guide layer having a vacuum state or an air layer is being recently proposed.